I need advice w my MILšŸ˜­

So a couple months ago I posted about my MIL and how me and my SO decided our baby wonā€™t be allowed around her and her bf unless we are around (I will post the post below) but now Iā€™m having issues with an upcoming 4D ultrasound. I have a 30 week ultrasound coming up on Saturday and I invited my MIL and she asked if she could bring her daughter and I told her I would think about it since Iā€™m not allowing my sister to go and she said ā€œitā€™s okay Iā€™ll just have her wait in the carā€ like okay so whatā€™s the point of her coming then? Anyways she then went on to say sheā€™s going to bring her boyfriend and GIRLS Iā€™m NOT comfortable with him coming. I was not raised around men I was raised by two lesbians who are my grandmas so having a man there in general is just super uncomfortable and not my thing. Not to mention heā€™s crazy and honestly has no business going heā€™s my SO UNCLE (I know, confusing) but if Iā€™m not inviting my SO dad then why should his uncle come? Heā€™s freaking nuts he told her 9 year old daughter on Friday he was going to kill my MIL like this man is just not someone I want there or around my son period. I donā€™t know how to tell her how I feel, usually Iā€™m a very upfront and blunt person but she is so sensitive and turns everything into something itā€™s not but Iā€™m now stressing about it. Itā€™s not her place to even invite people you know? Someone please just give me a way to tell her I only want her to come in a way that she wouldnā€™t freak out. I hate stressing about things. I feel I should not even have to stress about something like this but she wants to invite everyone and their damn dog I just donā€™t know what to došŸ˜­ she doesnā€™t take hints very easily she literally needs to be told how it is straight up but also in a way to where she wonā€™t act crazy I didnā€™t invite her to my first ultrasound and she freaked out she was crying and asking if sheā€™d ever be able to see the baby and made it about herself which is why Iā€™m having a hard time telling her.

My last post about her:

So itā€™s been a topic for me and my SO about how we will address certain issues involving our son and his mom and step dad. Every time and Iā€™m not kidding, EVERY TIME me and my SO decide to stop by his moms house to see her and his siblings his mom and her boyfriend are always fighting. He chases her up the stairs, threatens her etc in front of all of the kids (ages 9-14). I just feel like this isnā€™t a safe environment for my son. I donā€™t want him growing up around violence. Me and my SO have both decided our son wonā€™t be able to go around without us being there. Are we wrong for this decision? We havenā€™t had a talk with her yet about it but I know when we do sheā€™ll freak! I just want to be prepared for this upcoming war.